1. Field of the Invention
The present invention relates to an integrated circuit, a semiconductor device and an ID chip formed over a glass substrate or a flexible substrate. In addition, the invention relates to an integrated circuit, a semiconductor device and an ID chip that establish contactless communication.
2. Description of the Related Art
In recent years, a contactless IC card, ID tag, RFID or the like (hereinafter collectively referred to as an ID chip) having a high security function has been increasingly demanded for the purpose of ID management of securities, cashless electronic payment and the like by use of the ID chip. Such an ID chip incorporates highly functional integrated circuits such as a central processing circuit (typically referred to as a central processing unit and hereinafter also abbreviated to CPU) and a dedicated hardware having a cryptographic function.
An ID chip receives a power supply through a current induced by electromagnetic induction that is generated between a radio wave from a reader/writer and an antenna in the ID chip. However, according to such a method, the amount of power supplied to the ID chip changes when the positional relationship between the ID chip in operation and the reader/writer changes, and thus a stable power supply is difficult to be achieved.
In addition, since a CPU and a logic circuit for cryptographic operation occupy large circuit areas, a large power consumption is required. When a stable power supply is unavailable and a large power consumption is required, an operating margin is decreased, which hinders the stable operation. In addition, the large circuit area will lead to a lower impact resistance of the semiconductor device, and thus the number of chips taken from a silicon wafer is decreased, which leads to a higher cost.